Offline Gmail was one of the top requested features from businesses and schools considering Google Apps, and since launching this Labs feature almost a year ago, it's been been put through its paces, maturing along the way. We've made many improvements, including an option to choose which messages get downloaded for offline use and the ability to add message attachments while offline.

Today, Offline Gmail is graduating from Labs, becoming a core part of Gmail for everyone. You can turn it on and adjust your offline settings from the 'Offline' tab in Gmail 'Settings'.